scholarly journals DIPG-63. LOSS OF THE H4 LYSINE METHYLTRANSFERASE KMT5B DRIVES INVASION / MIGRATION BY DEPLETING H3K27me3 AT LOCI OTHERWISE RETAINED IN H3K27M MUTANT DIPG CELLS

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii299-iii300
Author(s):  
Ketty Kessler ◽  
Alan Mackay ◽  
Valeria Molinari ◽  
Haider Tari ◽  
Anna Burford ◽  
...  

Abstract Diffuse intrinsic pontine glioma (DIPG) and other diffuse midline glioma (DMG) are characterised by K27M mutations in histone H3 variants. The major functional consequence is a global loss of the repressive mark H3K27me3, causing a raft of transcriptional changes promoting tumorigenesis, although certain key loci retain trimethylation, such as CDKN2A/B. We recently identified subclonal loss-of-function mutations in the H4 lysine methyltransferase KMT5B to be associated with an enhanced invasion/migration, but the mechanism by which this occurred was unclear. Here we show by ChIP-seq using patient-derived subclonal DIPG models and CRISPR-Cas9 depletion that loss of KMT5B (or KMT5C) causes a paradoxical increase in global levels of H4K20me3 in promoters and regulatory regions, only ablated by knocking out both enzymes. Loss of KMT5B alone further causes loss of the majority of otherwise retained H3K27me3 loci in DIPG cells, although CDKN2A/B itself was spared. De-repression occurred at bivalent loci marked by H3K4me3 and had elevated gene expression by RNAseq; these were significantly enriched for genes involved in chromatin remodelling and invasion/migration, the latter including MMP9/MMP24. Phenotypic assessment of the models in vitro by high-throughput imaging demonstrated significantly increased invasion and migration in association with either KMT5B or KMT5C loss, but not both. Quantitative proteomic assessment of the secretome identified factors by which a minority of KMT5B-deficient cells may signal to promote motility of the neighbouring populations. These data suggest a previously unrecognised trans-histone (H4/H3) interaction in DIPG cells with a potentially profound effect on their diffusely infiltrating phenotype.

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii70-ii70
Author(s):  
Ketty Kessler ◽  
Alan Mackay ◽  
Valeria Molinari ◽  
Haider Tari ◽  
Anna Burford ◽  
...  

Abstract Diffuse intrinsic pontine glioma (DIPG) and other diffuse midline glioma (DMG) are characterised by K27M mutations in histone H3 variants. The major functional consequence is a global loss of the repressive mark H3K27me3, causing a raft of transcriptional changes promoting tumorigenesis, although certain key loci retain trimethylation, such as CDKN2A/B. We recently identified subclonal loss-of-function mutations in the H4 lysine methyltransferase KMT5B to be associated with an enhanced invasion/migration, but the mechanism by which this occurred was unclear. Here we show by ChIP-seq using patient-derived subclonal DIPG models and CRISPR-Cas9 depletion that loss of KMT5B (or KMT5C) causes a paradoxical increase in global levels of H4K20me3 in promoters and regulatory regions, only ablated by knocking out both enzymes. Loss of KMT5B alone further causes loss of the majority of otherwise retained H3K27me3 loci in DIPG cells, although CDKN2A/B itself was spared. De-repression occurred at bivalent loci marked by H3K4me3 and had elevated gene expression by RNAseq; these were significantly enriched for genes involved in chromatin remodelling and invasion/migration, the latter including MMP9/MMP24. Phenotypic assessment of the models in vitro by high-throughput imaging demonstrated significantly increased invasion and migration in association with either KMT5B or KMT5C loss, but not both. Quantitative proteomic assessment of the secretome identified factors by which a minority of KMT5B-deficient cells may signal to promote motility of the neighbouring populations. These data suggest a previously unrecognised trans-histone (H4/H3) interaction in DIPG cells with a potentially profound effect on their diffusely infiltrating phenotype.


2021 ◽  
Author(s):  
Ketty Kessler ◽  
Alan Mackay ◽  
Yura Grabovska ◽  
Valeria Molinari ◽  
Anna Burford ◽  
...  

DIPG are characterised by histone H3K27M mutations, resulting in global loss of the repressive mark H3K27me3, although certain key loci are retained. We recently identified subclonal loss-of-function mutations in the H4 lysine methyltransferase KMT5B to be associated with enhanced invasion/migration, but the mechanism by which this occurred was unclear. Here we use integrated ChIP-seq, ATAC-seq and RNA-seq on patient-derived, subclonal and CRISPR-Cas9-KD DIPG cells to show that loss of KMT5B/C causes depletion of these retained H3K27me3 loci via changes in chromatin accessibility, causing a raft of transcriptional changes which promote tumorigenesis. De-repression occurred at bivalent loci marked by H3K4me3, driving increased transcriptional heterogeneity and elevated gene expression associated with increased invasion, abrogated DNA repair and mesenchymal transition, along with a markedly altered secretome. These data suggest a previously unrecognised trans-histone (H4/H3) interaction in DIPG cells with a potentially profound effect on their diffusely infiltrating phenotype.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Shiwei Liu ◽  
Jingchao Li ◽  
Liang Kang ◽  
Yueyang Tian ◽  
Yuan Xue

Abstract Background Over the years, long non-coding RNAs (lncRNAs) have been clarified in malignancies, this research was focused on the role of lncRNA cartilage injury-related (lncRNA-CIR) in osteosarcoma cells. Methods LncRNA-CIR expression in osteosarcoma tissues and cells, and adjacent normal tissues and normal osteoblasts was determined, then the relations between lncRNA-CIR expression and the clinicopathological features, and between lncRNA-CIR expression and the prognosis of osteosarcoma patients were analyzed. Moreover, the MG63 and 143B cells were treated with silenced or overexpressed lncRNA-CIR, and then the proliferation, invasion, migration and apoptosis of the cells were evaluated by gain- and loss-of-function approaches. The tumor growth, and proliferation and apoptosis of osteosarcoma cells in vivo were observed by subcutaneous tumorigenesis in nude mice. Results We have found that lncRNA-CIR was up-regulated in osteosarcoma tissues and cells, which was respectively relative to adjacent normal tissues and normal osteoblasts. The expression of lncRNA-CIR was evidently correlated with disease stages, distant metastasis and differentiation of osteosarcoma patients, and the high expression of lncRNA-CIR indicated a poor prognosis. Furthermore, the reduction of lncRNA-CIR could restrict proliferation, invasion and migration, but promote apoptosis of osteosarcoma cells in vitro. Meanwhile, inhibited lncRNA-CIR also restrained tumor growth and osteosarcoma cell proliferation, whereas accelerated apoptosis of osteosarcoma cells in vivo. Conclusion We have found in this study that the inhibited lncRNA-CIR could decelerate proliferation, invasion and migration, but accelerate apoptosis of osteosarcoma cells, which may provide a novel target for osteosarcoma treatment.


2021 ◽  
Vol 49 (6) ◽  
pp. 030006052110132
Author(s):  
Hao Chen ◽  
Ye Zhang ◽  
Kankui Wu ◽  
Xiaoyong Qiu

Objective To study the relationship between the circular RNA vesicle-associated membrane protein-associated protein A (circVAPA) and the pathogenesis of oral squamous cell carcinoma. Methods The expression of circVAPA was detected by RT-qPCR. In vitro loss-of-function experiments were performed in Cal-27 cells. The malignant phenotype of cells was evaluated by cell counting kit-8, clone formation and transwell assays. Luciferase reporter assays were used to assess the circVAPA/miR-132/homeobox A (HOXA) regulatory axis. Results circVAPA expression was significantly increased in oral cancer tissues and cells. The overall survival and progression-free survival of patients with oral cancer who exhibited high circVAPA expression were significantly shorter compared with those with low expression. circVAPA expression was closely related to tumor size, TNM stage and distant metastasis. circVAPA knockdown reduced the proliferation, invasion and migration of Cal-27 cells. MiR-132 was identified as a target of circVAPA in Cal-27 cells. Cotransfection with si-circVAPA and miR-132 inhibitor reversed the inhibitory effect of circVAPA knockdown on cell malignant phenotypes. HOXA7 was further identified as a downstream target of miR-132. Conclusion circVAPA is highly expressed in oral cancer, and its abnormal expression might affect the proliferation, invasion and migration of oral cancer cells by modulating the miR-132/HOXA7 signaling axis.


Author(s):  
Xianxiong Ma ◽  
Hengyu Chen ◽  
Lei Li ◽  
Feng Yang ◽  
Chuanqing Wu ◽  
...  

Abstract Background Circular RNAs (circRNAs) are a class of non-coding RNA that play critical roles in the development and pathogenesis of various cancers. The circRNA circGSK3B (hsa_circ_0003763) has been shown to enhance cell proliferation, migration, and invasion in hepatocellular carcinoma. However, the specific functions and underlying mechanistic involvement of circGSK3B in gastric cancer (GC) have not yet been explored. Our study aimed to investigate the effect of circGSK3B on the progression of GC and to identify any potential mechanisms underlying this process. Methods CircRNA datasets associated with GC were obtained from the PubMed, GEO, and ArrayExpress databases, and circRNAs were validated via RT-qPCR and Sanger sequencing. Biotin-labeled RNA pull-down, mass spectrometry, RNA immunoprecipitation, and in vitro binding assays were employed to determine proteins demonstrating interactions with circGSK3B. Gene expression regulation was assessed through RT-qPCR, chromatin immunoprecipitation, and western blot assays. Gain- and loss-of-function assays were used to analyze any effects of circGSK3B and its partner regulatory molecule (EZH2) on the proliferation, invasion, and migration abilities of GC cells both in vitro and in vivo. Results CircGSK3B was mainly identified in the nucleus. This circRNA was present at a reduced concentration in GC tissues and cell lines. Overexpression of circGSK3B was shown to inhibit the growth, invasion, and metastasis of GC cells both in vitro and in vivo. Mechanistically, circGSK3B directly interacted with EZH2, acting to suppress the binding of EZH2 and H3K27me3 to the RORA promoter, and leading to an elevation in RORA expression and ultimately the suppression of GC progression. Conclusions CircGSK3B acts as a tumor suppressor, reducing EZH2 trans-inhibition and GC progression. This demonstrates the potential use of this RNA as a therapeutic target for GC.


2021 ◽  
Vol 22 (13) ◽  
pp. 7226
Author(s):  
Violeta Stojanovska ◽  
Aneri Shah ◽  
Katja Woidacki ◽  
Florence Fischer ◽  
Mario Bauer ◽  
...  

Cold shock Y-box binding protein-1 (YB-1) coordinates several molecular processes between the nucleus and the cytoplasm and plays a crucial role in cell function. Moreover, it is involved in cancer progression, invasion, and metastasis. As trophoblast cells share similar characteristics with cancer cells, we hypothesized that YB-1 might also be necessary for trophoblast functionality. In samples of patients with intrauterine growth restriction, YB-1 mRNA levels were decreased, while they were increased in preeclampsia and unchanged in spontaneous abortions when compared to normal pregnant controls. Studies with overexpression and downregulation of YB-1 were performed to assess the key trophoblast processes in two trophoblast cell lines HTR8/SVneo and JEG3. Overexpression of YB-1 or exposure of trophoblast cells to recombinant YB-1 caused enhanced proliferation, while knockdown of YB-1 lead to proliferative disadvantage in JEG3 or HTR8/SVneo cells. The invasion and migration properties were affected at different degrees among the trophoblast cell lines. Trophoblast expression of genes mediating migration, invasion, apoptosis, and inflammation was altered upon YB-1 downregulation. Moreover, IL-6 secretion was excessively increased in HTR8/SVneo. Ultimately, YB-1 directly binds to NF-κB enhancer mark in HTR8/SVneo cells. Our data show that YB-1 protein is important for trophoblast cell functioning and, when downregulated, leads to trophoblast disadvantage that at least in part is mediated by NF-κB.


2021 ◽  
pp. 1-9
Author(s):  
Huan Guo ◽  
Baozhen Zeng ◽  
Liqiong Wang ◽  
Chunlei Ge ◽  
Xianglin Zuo ◽  
...  

BACKGROUND: The incidence of lung cancer in Yunnan area ranks firstly in the world and underlying molecular mechanisms of lung cancer in Yunnan region are still unclear. We screened a novel potential oncogene CYP2S1 used mRNA microassay and bioinformation database. The function of CYP2S1 in lung cancer has not been reported. OBJECTIVE: To investigate the functions of CYP2S1 in lung cancer. METHODS: Immunohistochemistry and Real-time PCR were used to verify the expression of CYP2S1. Colony formation and Transwell assays were used to determine cell proliferation, invasion and migration. Xenograft assays were used to detected cell growth in vivo. RESULTS: CYP2S1 is significantly up-regulated in lung cancer tissues and cells. Knockdown CYP2S1 in lung cancer cells resulted in decrease cell proliferation, invasion and migration in vitro. Animal experiments showed downregulation of CYP2S1 inhibited lung cancer cell growth in vivo. GSEA analysis suggested that CYP2S1 played functions by regulating E2F targets and G2M checkpoint pathway which involved in cell cycle. Kaplan-Meier analysis indicated that patients with high CYP2S1 had markedly shorter event overall survival (OS) time. CONCLUSIONS: Our data demonstrate that CYP2S1 exerts tumor suppressor function in lung cancer. The high expression of CYP2S1 is an unfavorable prognostic marker for patient survival.


2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii295-iii295
Author(s):  
Mikaela Nevin ◽  
Janine Gallego ◽  
Xiaohua Song ◽  
Qiang Jiang ◽  
Alan Underhill ◽  
...  

Abstract BACKGROUND The identification of H3.3/H3.1K27M in most DIPG has changed our understanding of this disease. H3K27M mutations usually demonstrate global loss of H3K27 trimethylation (me3) with gain of H3K27 acetylation (ac). Single cell RNAseq has identified the putative cell of origin as oligodendroglial progenitor cells (OPC). The distalless gene family is necessary for the differentiation and tangential migration of committed neural progenitors to become GABAergic interneurons. Dlx1/Dlx2 double knockout (DKO) cells from the ganglionic eminences (GE) transplanted into a wild-type environment become oligodendrocytes. RESULTS We identified DLX2 occupancy of early (Olig2, Nkx2.2) and late (Myt1, Plp1) genes required for OPC differentiation in vivo and confirmed direct DLX2 protein-promoter DNA binding in vitro. Co-expression of Dlx2 with target sequences reduced reporter gene expression in vitro. There was increased expression of OLIG2, NKX2.2 and PLP-1 expression in vivo, consistent with de-repression in the absence of Dlx1/Dlx2 function. Transient over-expression of a Dlx2-GFP construct into murine DIPG cells from a GEMM that develops DIPG resulted in significant increases in expression of Gad isoforms with concomitant decreases in Olig2 and Nkx2.2. Dlx2-transfected mDIPG cells also demonstrated reduced migration, invasion and colony formation in vitro. Of significance, there was global restoration of H3K27me3 with corresponding loss of H3K27ac expression in transfected cells compared to controls. CONCLUSIONS DLX2 promotes GABAergic differentiation and migration while concomitantly repressing OPC differentiation in vivo. Developmental reprogramming of mDIPG cells by DLX2 demonstrates the potential role for directed differentiation strategies towards improving patient outcomes for this devastating pediatric cancer.


2018 ◽  
Vol 51 (3) ◽  
pp. 1276-1286 ◽  
Author(s):  
Feng Liang ◽  
Yu-Gang Wang ◽  
Changcheng Wang

Background/Aims: This study aimed at investigating the effects of metformin on the growth and metastasis of esophageal squamous cell carcinoma (ESCC) in vitro and in vivo. Methods: Two human ESCC cell lines EC9706 and Eca109 were selected and challenged with metformin in this study. Western blot assay was performed to detect th level of Bcl-2, Bax and Caspase-3. Scratch wound assay, transwell assay and Millicell invasion assay were used to assay the invasion and migration of EC9706 and Eca109 cells. Nude mice tumor models were used to assay the growth and lung metastasis of ESCC cells after metformin treatment. The plasma glucose level was also assayed. Results: We found that metformin significantly inhibited proliferation and induced apoptosis of both ESCC cell lines in a dose- and time-dependent manner, and the expression of Bcl-2 was down-regulated and Bax and Caspase-3 were up-regulated. Metformin significantly inhibited the invasion and migration of EC9706 and Eca109 cells (p < 0.05). mRNA and protein levels of MMP-2 and MMP-9 decreased significantly upon treatment with metformin of 10mM for 12, 24 and 48h in a time-dependent manner (p < 0.05). In line with in vitro results, in vivo experiments demonstrated that metformin inhibited tumorigenicity, inhibited lung metastasis and down-regulated the expression of MMP-2 and MMP-9. Moreover, we showed that metformin treatment did not cause significant alteration in liver and renal functions and plasma glucose level. Conclusion: Our study for the first time demonstrated the anti-invasive and anti-metastatic effects of metformin on human ESCC cells both in vitro and in vivo, which might be associated with the down-regulation of MMP-2 and MMP-9. As a whole, our results indicate the potential of metformin to be developed as a chemotherapeutic agent for patients with ESCC and might stimulate future studies on this area.


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